hello I wanted to change to my phaeton now gear oil and wanted to ask what is the best gear oil for it the engine must be warm or cold when draining the gear oil how much liter I have to buy to fill in and at which temperature I measure the gear oil and which flow I should best make I can run the gear oil over night somewhere I read that then about 9 liters come out altogether when you run over night is it meaningv oll original vw gear oil to fetch or what do you recommend to me ???